Opposition party Movement for Democratic Change (MDC) Vice President Thokozani Khupe spoke a news conference in the capital Harare, Zimbabwe on May 3. MDC continues to insist that it has won the March 29 election and does not need to participate in a planned runoff.

By restating its claimed victory, the likelihood of further confrontation between the two parties increases at a time of severe economic crisis and as pro-government militias continue a campaign of violence against opposition activists.

"We are convinced that the run-off is unnecessary considering the clear mandate that the people of Zimbabwe showed when they voted for change, dignity and jobs," Ms. Khupe said. "The MDC wishes to reiterate that this election was clearly won by the MDC.... It is for this reason that in the unlikely event of a run-off, the MDC will once again romp to victory by even a bigger margin."

If Zimbabwe's opposition is sending mixed signals, so is the country's ruling party.

Pro-government militias have reportedly beaten opposition activists in the past month – killing 20 MDC supporters and displacing some 5,000 families, opposition leaders say. Some top government officials speak openly about the possibility of a power-sharing agreement with the opposition, an unthinkable idea just weeks ago.

The willingness of the ruling ZANU-PF party – the former militia movement that overthrew white colonial rule in 1979 – to consider sharing power with the MDC, an opposition party it once derided as a British colonial stooge, speaks volumes about the weakness and fractures within that party and its desperate attempt to hold onto power after the March 29 vote.

A tipping point has clearly been reached: further confrontation and violence on one side, and a mediated compromise on the other.

This could be the moment for MDC leader Morgan Tsvangirai, says Gordon Moyo, director of Bulawayo Agenda, a coalition of civil-society groups in Zimbabwe's second-largest city. "The MDC has the edge now. Mr. Mugabe lost the election, and his ZANU-PF says it is prepared to form a government of national unity with the MDC."

But the opposition must be very careful about entering a runoff election, after weeks of violence against its members, 20 of whom have been killed by pro-Mugabe militias, Mr. Moyo says. He says the MDC should insist that it will only take part in elections if Zimbabwe's neighbors – under the umbrella organization SADC – observe the elections and insist that Mugabe stop using militias to intimidate voters.

"They must demand the disbanding of the war veterans' militia, and the withdrawal of the Army from communities. They can renew their call for the SADC to mediate, and prepare the conditions where a runoff can take place."

Ongoing violence around the country may make this a bad time to hold a runoff, says University of Zimbabwe political science lecturer Simon Badza. "To be honest this is not the right time for an election because it will not be indicative of the will of the people. People are being beaten and killed," said Mr. Badza.

Not even the intervention of SADC and the African Union (AU) would stop Mugabe's government from pursuing a violent election campaign because they are determined to hang on to power, Badza says.

"It would not help because Zimbabwe is exercising its own sense of sovereignty from an absolute sense. In times of political challenges like these ones, Mugabe does not listen to anyone."

• A journalist who could not be named for security reasons contributed from Harare.